The Infrared Astronomical Satellite (IRAS) mission

Neugebauer, G.; Habing, H. J.; Duinen, R. J. van; Aumann, Hartmut H.; Baud, B.; Beichman, Charles; Beintema, D. A.; Boggess, N. W.; Clegg, P. E.; Jong, T. de; Emerson, J. P.; Gautier, T. N.; Gillett, F. C.; Harris, S.; Hauser, M. G.; Houck, J. R.; Jennings, R. E.; Low, F. J.; Marsden, P.; Miley, G. K.; Olnon, F. M.; Pottasch, S. R.; Raimond, E.; Rowan-Robinson, M.; Soifer, B. T.; Walker, Russell G.; Wesselius, P. R.; Young, E. T.

doi:10.1086/184209

Cited by 855 publications

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“…A&A 557, A94 (2013) Notes. (a) Name of sources starting with numbers (e.g., 18151−1208) refer to the IRAS name (Neugebauer et al 1984). (b) Systemic velocity (V LSR ) derived from the hyperfine fit to the N 2 H + (1-0) and C 2 H (1-0) lines (see Sect.…”

Section: Introductionmentioning

confidence: 99%

Evolution and excitation conditions of outflows in high-mass star-forming regions

Sánchez-Monge

López-Sepulcre

Cesaroni

et al. 2013

A&A

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Context. Theoretical models suggest that massive stars form via disk-mediated accretion in a similar fashion to low-mass stars. In this scenario, bipolar outflows ejected along the disk axis play a fundamental role, and their study can help characterize the different evolutionary stages involved in the formation of a high-mass star. A recent study toward massive molecular outflows has revealed a decrease in the SiO line intensity as the object evolves. Aims. The present study aims to characterize the variation of the molecular outflow properties with time and to study the SiO excitation conditions in outflows associated with high-mass young stellar objects (YSOs). Methods. We used the IRAM 30-m telescope on Pico Veleta (Spain) to map 14 high-mass star-forming regions in the SiO (2-1), SiO (5-4), and HCO + (1-0) lines, which trace the molecular outflow emission. The FTS backend, covering a total frequency range of ∼15 GHz, allowed us to simultaneously map several dense gas (e.g., N 2 H + , C 2 H, NH 2 D, H 13 CN) and hot-core (CH 3 CN) tracers. We used the Hi-GAL data to improve the previous spectral energy distributions and obtained a more accurate dust envelope mass and bolometric luminosity for each source. We calculated the luminosity-to-mass ratio, which is believed to be a good indicator of the evolutionary stage of the YSO. Results. We detect SiO and HCO + outflow emission in all fourteen sources and bipolar structures in six of them. The outflow parameters are similar to those found toward other massive YSOs with luminosities 10 3 −10 4 L . We find an increase in the HCO + outflow energetics as the object evolves, and a decrease in the SiO abundance with time from 10 −8 to 10 −9 . The SiO (5-4) to (2-1) line ratio is found to be low at the ambient gas velocity, and increases as we move to red-/blue-shifted velocities, indicating that the excitation conditions of the SiO change with the velocity of the gas. In particular, the high-velocity SiO gas component seems to arise from regions with higher densities and/or temperatures than the SiO emission at the ambient gas velocity. Conclusions. The properties of the SiO and HCO + outflow emission suggest a scenario in which SiO is largely enhanced in the first evolutionary stages, probably owing to strong shocks produced by the protostellar jet. As the object evolves, the power of the jet would decrease and so does the SiO abundance. During this process, however, the material surrounding the protostar would have been been swept up by the jet, and the outflow activity, traced by entrained molecular material (HCO + ), would increase with time.

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Section: Introductionmentioning

confidence: 99%

Evolution and excitation conditions of outflows in high-mass star-forming regions

Sánchez-Monge

López-Sepulcre

Cesaroni

et al. 2013

A&A

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“…The target source of the present study is a dense core system in the Orion B9 star-forming region that consists of a candidate prestellar core and a Class 0/I protostar, namely the Infrared Astronomical Satellite (IRAS; Neugebauer et al 1984) source 05399-0121 (hereafter, I05399). This source has been the target of several previous studies, and what follows is an overview of these studies in chronological order.…”

Section: Introductionmentioning

confidence: 99%

SABOCA 350-μm and LABOCA 870-μm dust continuum imaging of IRAS 05399-0121: mapping the dust properties of a pre- and protostellar core system

Miettinen

Offner

2013

A&A

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Context. Thermal emission from dust provides a valuable tool for determining important physical properties of the dense structures within molecular clouds. Aims. We attempt to map the distributions of dust temperature and H 2 column density of IRAS 05399-0121/SMM 1, which is a dense double-core system in Orion B9. We also search for substructures within the cores through high-resolution submillimetre imaging. Methods. The source was mapped with APEX/SABOCA at 350 μm. We combined these data with our previous LABOCA 870-μm data. The spatial resolution of the new SABOCA image, ∼3400 AU, is about 2.6 times better than provided by LABOCA, and is therefore well-suited to our purposes. We also make use of the Spitzer infrared observations to characterise the star-formation activity in the source. Results. The filamentary source remains a double-core system on the 3400 AU scale probed here, and the projected separation between IRAS 05399 and SMM 1 is 0.14 pc. The temperature map reveals warm spots towards IRAS 05399 and the southeastern tip of the source. Both IRAS 05399 and SMM 1 stand out as peaks in the column density map. A simple analysis suggests that the density profile has the form ∼r −(2.3 +2.2 −0.9 ) , as determined at the position of SMM 1. The broadband spectral energy distribution of IRAS 05399 suggests that it is near the Stage 0/I borderline. A visual inspection of the Spitzer/IRAC images provides hints of a quadrupolar-like jet morphology around IRAS 05399, supporting the possibility that it is a binary system. Conclusions. The source splitting into two subcores along the long axis can be explained by cylindrical Jeans-type fragmentation, but the steepness of the density profile is shallower than what is expected for an isothermal cylinder. The difference between the evolutionary stages of IRAS 05399 (protostellar) and SMM 1 (starless) suggests that the former has experienced a phase of rapid mass accretion, supported by the very long outflow it drives. The protostellar jet from IRAS 05399 might have influenced the nearby core SMM 1. In particular, the temperature map features are likely to be imprints of protostellar or shock heating, while external heating could be provided by the nearby high-mass star-forming region NGC 2024.

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“…Aumann et al 1984;Neugebauer et al 1984), and studied by the Infrared Space Based on observations with APEX, Llano Chajnantor, Chile (OSO programme 081.F-9330(A)).…”

Section: Introductionmentioning

confidence: 99%

Kuiper belts around nearby stars

Nilsson

Liseau

Brandeker

et al. 2010

A&A

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Context. The existence of dusty debris disks around a large fraction of solar type main-sequence stars, inferred from excess far-IR and submillimetre emission compared to that expected from stellar photospheres, suggests that leftover planetesimal belts analogous to the asteroid-and comet reservoirs of the solar system are common. Aims. Sensitive submillimetre observations are essential to detect and characterise cold extended dust originating from collisions of small bodies in disks, belts, or rings at Kuiper-belt distances (30-50 AU or beyond). Measurements of the flux densities at these wavelengths will extend existing IR photometry and permit more detailed modelling of the Rayleigh-Jeans tail of the disks spectral energy distribution (SED), effectively constraining dust properties and disk extensions. By observing stars spanning from a few up to several hundred Myr, the evolution of debris disks during crucial phases of planet formation can be studied. Methods. We observed 22 exo-Kuiper-belt candidates at 870 μm, as part of a large programme with the LABOCA bolometer at the APEX telescope. Dust masses (or upper limits) were calculated from integrated 870 μm fluxes, and fits to the SED of detected sources revealed the fractional dust luminosities f dust , dust temperatures T dust , and power-law exponents β of the opacity law. Results. A total of 10 detections with at least 3σ significance were made, out of which five (HD 95086, HD 131835, HD 161868, HD 170773, and HD 207129) have previously never been detected at submillimetre wavelengths. Three additional sources are marginally detected with >2.5σ significance. The best-fit β parameters all lie between 0.1 and 0.8, in agreement with previous results indicating the presence of significantly larger grains than those in the ISM. From our relatively small sample we estimate f dust ∝ t −α , with α ∼ 0.8−2.0, and identify an evolution of the characteristic radial dust distance R dust that is consistent with the t 1/3 increase predicted from models of self-stirred collisions in debris disks.

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The Infrared Astronomical Satellite (IRAS) mission

Cited by 855 publications

References 0 publications

Evolution and excitation conditions of outflows in high-mass star-forming regions

Evolution and excitation conditions of outflows in high-mass star-forming regions

SABOCA 350-μm and LABOCA 870-μm dust continuum imaging of IRAS 05399-0121: mapping the dust properties of a pre- and protostellar core system

Kuiper belts around nearby stars

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